JP2005318632A - Non-contact transition part element between waveguide and microstrip feed line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new non-contact transition part between a waveguide structure and a structure that is realized, using a microstrip technology. <P>SOLUTION: The transition part element is installed between a waveguide (10) and a transition feed line on a substrate (30). The transition part element includes a fixed flange (20) on the substrate. In the fixed flange, in at least microstrip feed line direction, the size of the flange width d is such as to be selected to move the resonance mode, in the direction away from a useful bandwidth. Application: the element is used especially for a circuit which uses SMD technology at millimeter frequency. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transition element between a microstrip technology line circuit and a waveguide circuit, and more particularly a rectangle realized by using a technology based on a microstrip technology feed line and a metallized compact. This relates to a non-contact transition between the waveguide and the other waveguide.

  Wireless communication systems capable of transmitting high bit rates are currently greatly developed. Systems that are being developed, especially point-to-multipoint systems such as LMDS (Local Multi-Point Distribution System), WLAN (Wireless Local Area Network), are very high frequency, i.e. several It operates on the order of 10 GHz. While these systems are complex, they must be implemented at increasingly lower costs because they are intended for the mass consumer. Currently there are technologies such as LTCC (Low Temperature Sintered Ceramic) or HTCC (High Temperature Sintered Ceramic) technology, which integrate passive and active functions operating at the above frequencies to be realized at low cost on a planar substrate. Enable the device.

  However, some functions, especially the filtering function, are difficult to realize in the millimeter wave band. This is because the substrate to be used in this case does not have the required quality at the millimeter wave band level. Therefore, this type of function must be realized using a prior art substrate such as a waveguide. Thus, what arises is the interconnect between the waveguide and the printed circuit board, implemented using microstrip technology designed for use by other functions of the system.

  On the other hand, for the same reason mainly related to millimeter frequencies, antennas and their associated elements, such as filters, polarisers or orthomodes, are realized using waveguide technology. Therefore, it is necessary to be able to connect the circuit realized using the waveguide technology to the planar structure realized using the conventional printed circuit board technology, and this latest technology is suitable for mass production. It is configured.

  As a result, much research has been done on connections between waveguide structures and planar structures in microstrip technology. Therefore, Muller et al ,, EADS, page 1255 of a paper from the 33rd European Microwave Conference in Munich in 2003 entitled “Surface Mountable Plated Plastic Waveguide Filter Suitable for Mass Production”. Describes a waveguide filter that can be connected to a multilayer PCB (printed circuit board) by using SMD (surface mount component) technology. In this case, the input and output of the waveguide filter are soldered directly onto the footprint realized on the printed circuit board. These footprints provide a direct connection to the microstrip feeder. Therefore, waveguide mode excitation is performed by direct contact between the microstrip access feed line and the waveguide structure. Thus, this transition has been found to be complex to implement and requires strict manufacturing and positioning tolerances.

  The transition between the rectangular waveguide and the microstrip feed line was also made on January 3, 2003 by Thomson Licensing S.C. A. This is proposed in French patent application No. 0300045, filed in the name of the company. This transition part shapes the end of the waveguide in a special way, requires the microstrip feed line to be realized on the shaped substrate and extends to the foam structure where the ribbed waveguide is realized. In this case, the molded bar forming the waveguide is also used as a substrate for a microstrip feed line. This type of substrate is not always compatible with the realization of passive or active circuits.

  In all cases, the above-described embodiments are complex and lack flexibility.

  The present invention therefore proposes a novel non-contact type transition between the waveguide structure and the transition realized using microstrip technology. This transition is easy to implement and allows wide manufacturing and assembly tolerances. Furthermore, the transition part of the present invention is compatible with SMD mounting technology.

  The invention relates to a transition element for a contactless connection between a waveguide circuit and a microstrip technology feed line realized on a dielectric substrate. The transition element expands the end of the waveguide with a flange for fixing to the substrate, and the substrate has a conductive footprint for connection with the lower surface of the flange. In addition, in order to realize the application of the transition, a cavity with special dimensions is realized below the substrate and facing the end of the waveguide.

  The waveguide circuit and the fixed flange are realized in a block of synthetic material, such as a shaped body with a metallized outer surface except in the zone facing the cavity.

  The fixed flange is preferably integral with the end of the waveguide. However, for some embodiments, the fixed flange is an independent element secured to the end of the waveguide.

  According to a first embodiment, the fixed flange is dimensioned such that at least in the direction of the microstrip feed line, the flange width d is selected to move the resonance mode away from the useful band, , At least orthogonal to the end of the waveguide. In this case, the cavity has the same depth as λ / 4, where λ corresponds to the waveguide length in the waveguide and the microstrip feed line terminates with a probe.

  According to a second embodiment, the fixing flange is realized in the extension of the waveguide. In this case, the microstrip feed line terminates with a capacitive probe and the cavity has a depth between λ / 4 and λ / 2, where λ corresponds to the waveguide length in the waveguide . In order to prevent electrical leakage, a conductive footprint is realized on the substrate and can be connected to a C-shaped flange, and the open part between the C-shaped branches restricts electric field leakage while preventing short circuit The dimensions are as follows.

  According to a third embodiment, the waveguide is formed by hollowing out a dielectric block whose outer surface is metallized. In this case, the C-shaped conductive footprint realized on the substrate extends in the waveguide direction and forms the lower part of the waveguide. The footprint preferably includes a first metallization zone to which the waveguide is welded and a second metallization zone located within the first metallization zone and forming a cover for the waveguide. .

  Other features and advantages of the present invention will become apparent upon reading the description of various embodiments with reference to the accompanying drawings.

  With reference to FIGS. 1-4, a first description of a first embodiment of a transition element between a waveguide circuit and a microstrip feed line realized on a dielectric substrate is given.

  As schematically shown in FIG. 1 for the development of the transition element, reference numeral 10 schematically represents a rectangular waveguide. This waveguide is preferably realized by a synthetic material, and more specifically, it is preferably realized by a molded body having a dielectric constant remarkably similar to that of air. 11, the rectangular block of the molded body realizes a microwave waveguide by metallizing all outer surfaces.

  As particularly shown in FIGS. 1 and 3, a flange 20 having a pronounced C-shape is realized at one end of the waveguide 10, and preferably at the same time as a molded-body waveguide. The flange 20 surrounds the rectangular end of the waveguide 10 with its two short sides and one long side, whereas the other long side has an opening 22 which is dielectric. Located to prevent any short circuit with the microstrip feed line 31 realized on the substrate 30.

  As more clearly shown in FIG. 3, the assembly formed by the rectangular waveguide and the transition constituted by the flange is metallized 11 and 23. However, the end corresponding to the output of the waveguide that forms a rectangular zone with the zone at the level of the cut of the flange 20 in the vertical direction is not metallized as indicated by 24.

  Constructed by a partially metallized green body structure, this flange forms an overfrequency cavity that can compromise and degrade migration performance. To prevent this problem, in accordance with the present invention, the flange 20 is specially sized to obtain reliable electrical contact with the substrate mounting the microstrip technology circuit, as described below. In addition, good mechanical support for the assembly is ensured by eliminating resonant modes.

  Therefore, the portion of the flange 20 opposite the non-metallized portion, corresponding to the opposite portion of the microstrip feedline, is dimensioned to move the resonant frequency of the flange out of the useful band. The thickness of the flange selected according to the required mechanical strength, i.e. the dimension d of this part of the flange, is selected such that the resonant frequency generated is outside the useful band. Further, as shown in FIG. 1, the microstrip technology circuit is implemented on a dielectric substrate 30. More specifically, as shown in FIG. 2, the dielectric substrate 30 includes a metal layer 30a, thereby forming a ground plane on the lower surface. The ground plane comprises a rectangular non-metallized zone 30 b corresponding to the rectangular output of the waveguide 10, which is adjacent to the cavity 40 realized in the box or base 40 that supports the substrate 30. doing. These are described in detail below.

  The top surface of the substrate shown in FIG. 2a has a microstrip technology feed line 31a extended by an impedance matching feed line 31b using microstrip technology and a connection for recovering the energy emitted by the waveguide 10. Element or probe 31c. This element is known by the technical term “probe” in English.

  In order to allow a connection between the waveguide output and the probe 31c, a footprint 30c on the bottom surface of the flange 20 is realized in the conductive material on the top surface of the substrate 30. As clearly shown in FIG. 2a, the portion of the footprint found in the extension of the probe 31c has a width d corresponding to the width d of the portion of the flange 20 shown in FIG.

  The metallization zone 30c is used to receive the corresponding surface of the flange connected by welding, more specifically soldering, which metallization zone is below the ground plane 30a by a metal hole not shown. Is electrically connected.

  Further, as shown in FIG. 1, a dielectric substrate that accepts a microstrip technology circuit is mounted on a metal base or metal box 40 having a cavity 41 in the portion facing the waveguide. The cavity has an opening that is the same size as the rectangular waveguide opening and a depth that is significantly the same as one-fourth of the waveguide length in the waveguide. This is to provide impedance matching for the transition.

  For the present invention, only the width of the flange portion of the transition portion seen in the same direction as the microstrip technology feed line is important in relation to the resonance phenomenon. Indeed, for a rectangular waveguide as shown in FIG. 1, the fundamental mode TE10 is excited, the electric field is greatest in the axis of the access feed line, and quasi-laterally on the short side of the waveguide. Zero. Therefore, cavities formed on either side of the microstrip feed line and in the vicinity of the lateral members of the flange have little effect on performance, and the size of these portions of the flange is Selected only to provide mechanical rigidity of the assembly. On the other hand, for the rear flange part, it is excited by the feeder and generates a resonance frequency depending on the size of this part. This frequency is in the useful band. Thus, the width d is selected to move this frequency out of the useful band and the height is selected according to mechanical limitations.

  In order to confirm the above concept, by using simulation software known as “Ansoft / HFSS” using the finite element method, a transition structure associated with a planar structure in the form of FIG. 1 and a rectangular waveguide. The device was simulated electromagnetically in 3D. In this case, a waveguide named WR28 having a tube cross section of 3.556 mm × 7.112 mm is expanded by a flange as shown in FIG. A flange having a thickness of 1.5 mm, a short side width of 2 mm, and a width equal to 4 mm or 2.3 mm, as described above, has a thickness of 0.2 mm known by the trade name RO4003. It is mounted on a low-cost microwave substrate, and a microstrip feed line is realized on this substrate.

  Furthermore, the waveguide is realized by metallizing a molding material known by the trade name “Rohacell / HF71”. This material exhibits a very low dielectric constant and low dielectric loss, where εr = 1.09, tg, δ = 0.001, up to 60 GHz. The results of this simulation are shown in FIGS. 4a and 4b, where d = 4 mm in FIG. 4a and d = 2.3 mm in FIG. 4b.

  For d = 4 mm, excellent impedance matching around 18 dB is observed over the 27-32 GHz frequency band, whereas for d = 2.3 mm, catastrophic resonances are seen around 29 GHz. Observed.

  In FIG. 5, another embodiment of the present invention is shown. In this case, as indicated by reference numeral 101, the waveguide 100 is a tube bent at 90 ° and includes a flange 102 at the end, and the assembly is made using molded body technology, ie, as described above. This is realized by rolling the compact block and coating it with a metal layer. The flange 102 is of the same type as the flange shown in FIG. Flange 102 has a “C” shape and has an opening 103 in the portion that must face the microstrip technology feed line to be coupled to the waveguide.

  As shown in FIG. 5, a substrate 110 of the same type as the substrate 30 of FIGS. 1 and 2 has a microstrip technology feed line 111 and a conductive footprint 112 for fixing the flange 102. This footprint 112 shows a dimension d with the value determined as described above in such a way that on the opposite side of the feed line 111 the resonance frequency of this part is moved out of the useful band.

  In the same manner as the embodiment of FIG. 1, the substrate is mounted on a metal base or metal box, the height of which is the same as λ / 4, where λ is the waveguide length in the waveguide. is there.

  This type of system was simulated by using the same software as described above, using the same materials for the substrate and the waveguide. The dimensions of the bend 101 were optimized for application near 30 GHz. A curve for impedance matching as a function of frequency is shown in FIG. It shows an impedance matching of 20 dB or more with a bandwidth around 30 GHz.

  In FIG. 7, another embodiment with two waveguide / planar substrate transitions is shown. More specifically, the straight waveguide 200 realized by using the molded body technique is extended by 90 ° bent portions 201a and 201b at each end. Each curved end is extended by flanges 102a, 102b, similar to that described with reference to FIG. This flange is used to connect the waveguide 200 to input and output circuits implemented in microstrip technology on a planar substrate of microwave dielectric material. The same types of footprints 211a and 211b as the footprint 112 of FIG. 5 are realized at the level of the transition portion of each waveguide end provided with the microstrip feed line on the substrate. These footprints surround the non-metallized portions 213a, 213b and the ends (or probes) of the microstrip feed lines 212a, 212b used to supply the circuit implemented using planar technology are non-metallized portions. Has reached in. The substrate 210 is mounted on a metal base or metal box 220, and the metal base has cavities opposite the ends 201a, 201b of the waveguide 200, as with FIG. The cavity is sized similar to the embodiment of FIG.

  This type of structure is simulated as described above, and the simulation results for impedance matching are shown in FIG.

  In this case, the level of loss is close to that obtained for a single transition at 30 GHz, and for 42 mm wavelength, the simulated insertion loss is 1.5 dB.

  As described above, the dimension d is selected such that the cavity formed by the portion of the flange opposite the portion corresponding to the microstrip feed line resonates at a frequency outside the useful band frequency. To achieve this, the resonance frequency of this part depends not only on the value of d, but also on the height and width of this part of the flange. These last two dimensions are chosen so that the flange is mechanically rigid. Thus, d is a value that is inversely proportional to the frequency for the selected height and base width. The curve in FIG. 9 shows the change in resonance frequency as a function of the flange width d. For example, for a system operating with a bandwidth of 27-29 GHz, the value of d must be well above 2.5 mm so that the resonant frequency is moved considerably away from the useful bandwidth.

  10 to 17, another embodiment of the transition element according to the present invention will now be described. In this case, the waveguide circuit 50 includes a rectangular waveguide 51 and the end of the waveguide is widened by a flange 52 for securing to a planar technology circuit, specifically a substrate 60 having a microstrip. It has been.

  In this embodiment, the lower surface 52a of the flange 52 extends the lower part 51a of the rectangular waveguide so that the entire waveguide is located on the substrate 60. Further, the end portion of the rectangular waveguide is terminated by the inclined portion 53. With respect to the first embodiment, the rectangular waveguide 50 is realized in a solid block of synthetic fiber and can be of the same type as used in the embodiment of FIG. With the exception of zone 54 and zone 55, the outer surfaces of the waveguide and flange are metallized. In order to prevent any short circuit, the zone 54 is rectangular in the illustrated embodiment and is located above the impedance matching cavity 71, which will be described in detail later, and the zone 55 includes a microstrip technology feed line, a molded body block, The interface between is located vertically.

  In order to achieve a contactless connection with planar technology circuitry, more specifically with microstrip technology, a substrate 60 of dielectric material includes a lower ground plane 60a, as shown in FIGS. 1, 2a and 2b, The lower ground plane has a non-metallized zone 60b at a portion located opposite the cavity 71.

  On the upper surface 60c of the substrate, an access power supply line 60d that terminates with a probe 60e is realized by a microstrip technique, and in this case, is dimensioned so as to be capacitive.

  Further, in order to realize the mounting of the waveguide 50 to the substrate 60, the probe 60e is surrounded by a conductive footprint 60f having a molded body corresponding to the lower surface of the flange 52. The attachment of the flange to the footprint is made by welding, more specifically by soldering or any other equivalent means. The footprint shape is described in detail below. Furthermore, the footprint 60f is electrically connected to the ground plane 60a by a metallized hole (not shown).

  Further, the substrate 60 is mounted on a metal base or metal unit 70. For the purposes of the present invention, the metal base includes a cavity 71 that is shaped or rolled in the base 70 at the level of the transition. Cavity 71 preferably has the same cross-section as a rectangular waveguide and a depth between λ / 4 and λ / 2, where λ represents the waveguide length within the waveguide. The exact dimensions of the depth are selected to optimize the response of the transition element.

  In this embodiment, the flange dimensions not only facilitate correct offset of the waveguide on the substrate, but also provide reliable electrical contact with the printed circuit at the transition level. It is implemented to provide ground coupling for the entire assembly while avoiding power leakage. By the way, the flange includes an extra frequency cavity that can interfere with the performance of the transition and reduce the performance of the transition. Therefore, the flange must be sized correctly.

  In this case, the TE10 mode is excited. Therefore, the structure of the electric field is maximal on the axis of the access feed line and is almost zero laterally on the short side of the waveguide.

  Thus, the portion of the flange that forms the cavity located on either side of the access feeder has little spurious effect on system performance. However, the size of the opening 55 in the flange 52, which is essential for the input of the microstrip feed line 60d, is important. In order to prevent disturbances associated with the coupling between the microstrip access feeder and the metallization zone of the flange, it is necessary to provide sufficient space. Conversely, an aperture that is too large is a direct cause of a significant increase in leakage by being located in a highly concentrated zone of the electric field.

  The following embodiment was simulated using the same method as described for the embodiment of FIG. Therefore, a microstrip feed line realized on a low-cost substrate formed of a dielectric material named ROGERS RO4003 with a thickness of 0.2 mm, and a high standard section WR28: 3.556 mm x 7.112 mm For a transition element to and from a waveguide as shown in FIG. 10 realized with a low loss material (such as the molded product known under the trade name ROACELL HF71) with a length of 1 mm, around 30 GHz The results of a simulation using the dimensions of a waveguide designed to operate are shown in FIG.

  In this case, the following results were obtained.

Impedance matching over 20 dB over a very wide bandwidth ranging from 22.2 to 30.8 GHz.

-Impedance matching of 25 dB or more from 28.9 to 30.1 GHz.

・ Remarkably low insertion loss on the order of 25 dB

  The effect of flange 52 dimensions on transition optimization is described below with reference to FIGS. FIG. 13 is a top view schematically showing the transition element when the waveguide is mounted on a substrate. In this case, the flange 52 includes two cavities 52b projecting laterally with respect to the lateral wall of the waveguide 51 itself. These two cavities extend in the vicinity of the vertical cavity 52a having an opening 52c in the center and correspond to the path of the microstrip feed line. In this embodiment, as described above, the size of the opening 52c has an effect on the electrical performance of the transition, such as insertion loss (S21) and return loss (S11).

  Therefore, as shown in FIG. 14, FIG. 14 shows the insertion loss S21 as a function of the width of the opening 52a, and it can be seen that there are three distinct zones:

• For apertures of 8 mm or less, the loss is significant, reflecting the phenomenon of coupling between the feed line and the metallized wall of the waveguide.

• For apertures between 8 mm and 2 mm, an optimal value range is observed where the transition loss is on the order of -0.25 dB and minimal.

• For apertures greater than 2 mm, the loss begins to increase, resulting in increased field leakage.

  Further, FIG. 15 shows the return loss as a function of the aperture width d as seen for each of the three zones. Therefore, the following points are observed.

• For apertures of 8 mm or less, the return loss response of the structure is completely disturbed. The presence of cavity ends that are too close introduces significant misalignment.

• For apertures between 8 and 2 mm, impedance matching is optimized and covers the operating bandwidth.

• For openings larger than 2 mm, a level of ridges has started that is related to leakage due to openings that are too wide.

  FIGS. 16 and 17 show the effect of the widths a and b of the cavities 52a, 52b forming the flange on the performance of the transition.

For cavity a, FIG. 16 shows that the width of this cavity has only a minor effect on the return loss response of the transition. In a wide frequency band, the loss always remains below -15 dB for a wide range of 0.2-1.5 mm.

Regarding the width of the cavity b, FIG. 17 shows that by doubling its value from 1 mm to 2 mm, the return loss always remains below −17 dB in a very wide frequency band, which is the performance of the transition part. It shows that it inhibits only a little.

  18 and 19 schematically show two other embodiments of a waveguide circuit used in a transition element of the type described with reference to FIG.

  With respect to FIG. 18, the waveguide 500 is a three-order apertured waveguide filter that exhibits a Chebyshev-type response. Waveguide 500 is connected to a planar technology circuit by using a transition element as described above. Thus, FIG. 18a schematically shows a substrate 501 characterized by having a connection footprint and access feed line and a base 502 characterized by having a cavity facing the output of the filter 500. FIG. Yes.

  The performance associated with this embodiment is shown in FIG. 18b. The following results can be seen.

Low insertion loss on the order of 1.2 dB for frequencies in the 900 MHz range near 30 GHz.

-Return loss of -23 dB or less in the same frequency range.

  FIG. 19 is similar to FIG. 18 and shows a waveguide 600 that includes a quasi-elliptical filter containing two stubs located at each input of the waveguide. The purpose of this device is to increase the selectivity of the filter by generating transmission zeros outside the bandpass locally. A filter 600 surface mounted on a substrate 601 (RO4003) and a base 602 characterized by having a cavity and excited by two microstrip feed lines was fully simulated in 3D. FIG. 18b shows the performance obtained.

-Insertion loss of the order of 1.2 dB in the 1 GHz passband near 30 GHz.

-Return loss of -30 dB or less with a bandwidth of 29.5 to 30.0 GHz

• Attenuation of 60 dB or more at 28.55 GHz, where 28.55 GHz is the frequency corresponding to the rejected spurious frequency.

  With reference to FIGS. 20 to 22, another embodiment of a transition element according to the present invention is described below. In this case, the waveguide circuit 80 includes a rectangular waveguide 81, the end of which is widened by an element 82 that forms a fixed flange. In this embodiment, the waveguide is formed by a block of dielectric material, which may be a molded body of synthetic fiber having the same dielectric constant as air. The block is hollowed out to form a cavity 83, and the outer surface of the block is fully metallized. Further, the flange 82 has a slot 84, the role of which will be described later. In an embodiment, the lower surface of the flange 82 extends into the hollowed out portion of the rectangular waveguide 81 so that the waveguide is located on a planar technical circuit, in particular a substrate 90 that receives a microstrip feed line.

  As shown in FIGS. 20 and 21, the substrate 90 of microwave dielectric material includes a shaped body plane marked 94 in FIG. 21a, which ground plane is at the level of the waveguide at the transition level. A non-metallized region 95 is provided in a portion located opposite to the portion. Further, in this embodiment, the top surface of the substrate 90 includes a first metallization zone 93b that is used to offset the waveguide 80.

  This zone 93b is electrically connected to the ground plane 94 by a metallized hole (not shown). In addition, the substrate 90 includes a second metallization zone 93a located within the zone 93b and extends below the entire opening of the waveguide 80 to cover the opening 83 of the waveguide.

  The top surface of the substrate 90 also includes a non-metallized zone 96 corresponding to the zone 95. This zone 96 receives the end 92 or “probe” of the feeder 91 realized by printed circuit technology, in particular by microstrip. This feed line traverses a non-metallized zone in zone 93 a corresponding to gap 84 in flange 82.

  The assembly is mounted on a metal base or metal box 72. In the context of the present invention, the metal base includes a cavity 73 at the level of the transition that has been cast or rolled into the base. The cavity has a cross section that is significantly identical to the cross section of the end of the waveguide. That is, it corresponds to the non-metallized zone 95 and the depth between λ / 4 and λ / 2, where λ represents the waveguide length in the waveguide.

  The embodiment described above was simulated using the same method as described for the previous embodiment. The substrate is therefore composed of a dielectric material known under the name ROGERS RO4003 with a thickness of 0.2 mm. The waveguide is realized in a block of rolled dielectric material in such a way that the internal cross section of the waveguide is equivalent to the standard WR28: 3.556 mm × 7.112 mm and exhibits a thickness of 2 mm. Yes. The waveguide is metallized with a conductive material such as tin, copper or the like. The system is set to operate at 30 GHz.

  In this case, as shown in FIG. 22 for a single microstrip feed / waveguide transition, the following results are obtained:

-Impedance matching of 15 dB or more in a very large band ranging from 26 GHz to 36 GHz.

A considerably low return loss on the order of 0.4 dB in this frequency band.

  The waveguide 80 is located at each input of a diaphragm waveguide filter or a waveguide of the type shown in FIG. 19, characterized by having a Chebyshev-type response of the type shown in FIG. It will be apparent to those skilled in the art that it can be modified to implement a quasi-elliptical filter with two stubs.

  It will be apparent to those skilled in the art that many variations can be made to the embodiments described above. In particular, it would be envisaged to insert the end of the waveguide into a separate transition element for some embodiments. The important point is to realize a non-contact transition that does not exhibit a spurious resonance mode.

FIG. 2 is a developed perspective view showing a first embodiment of a transition element between a waveguide circuit and a microstrip technology feed line according to the present invention. (A) is a top view of a substrate including a microstrip technology feed line used in the first embodiment, and (b) is a bottom view of a substrate including a microstrip technology feed line used in the first embodiment. It is. It is a perspective view which shows the transition part element integrated with the waveguide. (A) and (b) are curve graphs showing application as a function of frequency for the dimension d of the flange in the microstrip feed direction for the embodiment of FIG. 1, eg, d = 4 mm and d, respectively. = 2.3 mm. FIG. 6 is an exploded perspective view showing an element between a microstrip feed line and a waveguide bent at 90 ° according to a second embodiment. 6 is a curve graph showing impedance matching and transition loss as a function of frequency for the embodiment of FIG. It is an expansion | deployment perspective view which shows the other deformation | transformation of a 1st embodiment regarding the waveguide provided with two 90 degree bending parts. 8 is a curve graph showing impedance matching and transition loss as a function of frequency for the embodiment of FIG. 4 is a curve graph showing the change in resonance frequency as a function of the dimension d, allowing the limit value of d to be determined. FIG. 5 is a developed perspective view showing a second embodiment of a transition element between a waveguide circuit and a microstrip technology feed line according to the present invention. (A) And (b) is the top view and bottom view of a board | substrate containing the microstrip technology electric power feeding line used in the 2nd embodiment, respectively. 11 is a curve graph showing simulated insertion loss and return loss for a transition between a waveguide and a microstrip feed line according to FIG. FIG. 11 is an enlarged bottom view showing a conductive footprint and a microstrip feed line on a substrate for the embodiment of FIG. 11 is a curve graph showing insertion loss as a function of footprint aperture width for the embodiment of FIG. 10 at 30 GHz. It is a curve graph which shows the return loss amount regarding a different footprint dimension. It is a curve graph which shows the return loss amount regarding a different footprint dimension. It is a curve graph which shows the return loss amount regarding a different footprint dimension. (A) is an exploded perspective view showing a variation of the embodiment of FIG. 10 for a waveguide circuit including an SMD filter, and (b) is a curve showing simulated impedance matching and return loss for this variation. It is a graph. (A) is an exploded perspective view showing another variation of the embodiment of FIG. 10 for a waveguide circuit including an SMD pseudo-elliptic filter, and (b) is a simulated impedance matching and return attenuation for this variation. It is a curve graph which shows quantity. FIG. 5 is a developed perspective view showing a second embodiment of a transition element between a waveguide circuit and a microstrip technology feed line according to the present invention. (A) And (b) is the bottom view and top view which respectively show the board | substrate containing the microstrip technology electric power feeding line used in 3rd embodiment. FIG. 21 is a curve graph showing simulated insertion loss and return loss for a transition according to FIG. 20.

Explanation of symbols

10 Waveguide 20 Flange 30 Substrate 30a Ground plane 30b Non-metallized zone 30c Footprint 31 Microstrip technology feed line 31a Microstrip technology feed line 31b Impedance matching feed line 31c Probe 32 Footprint 41 Cavity 50 Waveguide 51a Lower part 52 Flange 52a Cavity 52b Cavity 52c Opening 53 Slope 54 Non-metallized zone 55 Non-metallized zone 60 Substrate 60a Lower ground plane 60b Non-metallized zone 60c Top surface 60d Access feed line 60e Probe 60f Footprint 70 Metal base 71 Cavity 80 Waveguide Tube circuit 81 Waveguide 82 Flange 83 Cavity 84 Slot 90 Substrate 93a First metallization zone 93b Second metallization zone 94 Ground plane 95 Nonmetallized region 96 Nonmetallized 100 Waveguide 101 Bent portion 102 Flange 110 Substrate 111 Microstrip technology feeder 112 Footprint 200 Waveguide 201a Bent portion 201b Bent portion 210 Substrate 211a Footprint 211b Footprint 212a Microstrip feeder 212b Microstrip feeder 213a Non-metallized part 213b Non-metallized part 600 Waveguide 601 Substrate 602 Base

Claims (14)

A transition element for contactless connection between a waveguide circuit and a microstrip technology feed line realized on a dielectric substrate,
The transition element is enlarged by a flange at the end of the waveguide for fixing to the substrate,
The substrate has a conductive footprint for connection with the lower surface of the flange;
A transition section characterized in that a cavity dimensioned to achieve impedance matching with the waveguide circuit is realized below the substrate and opposite the end of the waveguide. element.   2. The waveguide circuit and the fixed flange are realized in a block of synthetic material, such as a molded body with a metallized outer surface except in a zone facing the cavity. Transition part element as described in.   The transition element according to claim 1, wherein the fixing flange is integral with an end of the waveguide.   The transition element according to claim 1, wherein the fixing flange is a separate element fixed to an end of the waveguide.   The fixed flange is dimensioned such that at least in the direction of the microstrip feedline, the width d of the flange is selected to move the resonant mode away from the useful band; 5. A transition element according to claim 3, wherein the transition element is at least orthogonal to the end of the tube.   The cavity according to any one of claims 3 to 5, wherein the cavity has the same depth as λ / 4, where λ corresponds to a waveguide length in the waveguide. The transition element described.   The transition element according to claim 3, wherein the microstrip feed line is terminated with a probe.   The transition element according to claim 3, wherein the fixed flange is realized in an extension of the waveguide.   The transition of claim 8, wherein the cavity has a depth between λ / 4 and λ / 2, where λ corresponds to a waveguide length in the waveguide. Element.   10. The transition element according to claim 8, wherein the microstrip feed line is terminated with a probe.   The conductive footprint has a C-shape, and an open portion between the C-shaped branches is dimensioned to limit electric field leakage while preventing a short circuit. A transition element according to claim 8.   4. The transition element according to claim 1, wherein the waveguide is formed by hollowing out a dielectric block whose outer surface is metallized.   The transition element according to claim 12, wherein the conductive footprint extends below a hollowed portion of the waveguide to form a cover.   The conductive footprint implemented on the substrate includes a first metallization zone to which the waveguide is fixed, and a second metallization zone in the first metallization zone, the second metal 14. A transition element according to claim 12 or 13, characterized in that the activation zone forms a cover for the waveguide.

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